口蓋に発生した上皮筋上皮癌の1例

Epithelial-myoepithelial Carcinoma in Hard Palate:Report of a Case

　はじめに

　Donathらが1972年に報告した上皮筋上皮癌は，介在導管細胞由来と考えられているまれな唾液腺悪性腫瘍で，その頻度は全唾液腺腫瘍の1％以下と推測されている^1）。この腫瘍は，そのほとんどが大唾液腺に発生するといわれ^2），本邦では小唾液腺原発の報告は非常に少ない^3〜5）。今回われわれは硬口蓋に発生した小唾液腺由来と考えられる上皮筋上皮癌を経験したので，若干の文献的考察を加え報告する。

A rare case of epithelial-myoepithelial car-cinoma, originating from the minor salivary glands, was reported. A 71-year-old woman presented with an asymptomatic tumor in the hard palate. Micro-scopically the tumor showed a biphasic tubular structure which consisted of inner eosihophilic cells and outer clear cells. Immunohistochemical study showed that the inner cells were positive for cyto- keratin, epithelial membrane antigen and car-cinoembryonic antigen while the outer cells were positive for S100, cytokeratin and muscle actin. This result suggested that the inner and outer cells showed epithelial and myoepithelial differentiation respectively.